1. Field of the Invention
The present invention relates to spandex in which particles of barium sulfate are dispersed and, more specifically, to spandex wherein the barium sulfate particles have a very low isoelectric point.
2. Description of the Prior Art
Spandex is known to exhibit considerable tackiness compared to conventional non-elastomeric textile fibers. The filaments tend to stick to various surfaces and to each other, especially when wound up on a bobbin. Tackiness can cause excessive unwinding tension (referred to hereinafter as "take-off tension") as well as frequent, large transients in the tension as the spandex is unwound from the package. Excessive take-off tensions and transients can cause yarn breaks during handling, fabric defects and other manufacturing difficulties, especially in making of knit fabrics.
To reduce spandex tackiness, lubricating finishes and other materials have been applied to spandex and/or dispersed within the spandex. Examples of such lubricating finishes include metallic soaps dispersed in textile oils (Yuk, U.S. Pat. No. 3,039,895) and polyalkylsiloxanes (Chandler, U.S. Pat. No. 3,296,063). The dispersion of certain metal soaps (e.g., stearates of calcium, magnesium or lithium) within the spandex for tackiness reduction is disclosed by Hanzel et al, U.S. Pat. No. 4,296,174.
Imai et al, U.S. Pat. No. 4,525,420, disclose the use of inorganic fillers, including barium sulfate, having a refractive index of .ltoreq.1.75, to improve the spinning properties and light and chlorine resistance of polyurethane elastic yarn. The spinning properties are said to be improved because filament breakage is decreased through the prevention of turbulence and melt adhesion of the filaments in the spinning tube.